Regulation of Cellular Oxygen Sensing Pathways by VHL.

Regulation of Cellular Oxygen Sensing Pathways by VHL.

Author: Pardeep Heir

Publisher:

Published: 2015

Total Pages:

ISBN-13:

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Erythropoiesis represents a vital physiologic process that can be adjusted to combat compromised oxygen availability, otherwise known as hypoxia. The canonical response to adapt to hypoxia is mediated by the transcription factor hypoxia-inducible factor-1 (HIF-1). When oxygen is available HIFalpha subunits are hydroxylated by prolyl hydroxylase enzymes (PHD1-3) to allow for binding to the von Hippel-Lindau (VHL) tumour suppressor protein, which serves as the substrate recognition subunit of an E3-ubiquitin ligase complex that ultimately targets proteins for proteasome-mediated degradation. The work presented in this thesis demonstrates a novel role of VHL in recruiting DCNL1 to initiate E3-ubiquitin ligase enzymatic activity which, in essence, allows for the degradation of HIFalpha to commence. In hypoxia, hydroxylation does not take place and as a result HIFalpha can promote the transactivation of a repertoire of genes that aid in adaptation to hypoxia including one which encodes the glycoprotein hormone erythropoietin (EPO). EPO binds to EPO receptor (EPOR) expressed on erythroid progenitor cells to promote their proliferation and differentiation into red blood cells. An erythroid specific oxygen sensing pathway is elucidated in this thesis wherein EPOR is hydroxylated by PHD3 to promote VHL-mediated degradation in a manner analogous to HIFalpha. Combined, these findings build upon our fundamental understanding of how cells detect and counter hypoxic stress.


Oxygen Sensing

Oxygen Sensing

Author:

Publisher: Elsevier

Published: 2004-05-10

Total Pages: 867

ISBN-13: 0080497195

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The ability of cells to sense and respond to changes in oxygenation underlies a multitude of developmental, physiological, and pathological processes. This volume provides a comprehensive compendium of experimental approaches to the study of oxygen sensing in 48 chapters that are written by leaders in their fields.


Hypoxia

Hypoxia

Author: Robert C. Roach

Publisher: Springer Science & Business Media

Published: 2002-01-31

Total Pages: 466

ISBN-13: 9780306466960

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Hypoxia remains a constant threat throughout life. It is for this reason that the International Hypoxia Society strives to maintain a near quarter century tradition of presenting a stimulating blend of clinical and basic science discussions. International experts from many fields have focused on the state-of-the-art discoveries in normal and pathophysiological responses to hypoxia. Topics in this volume include gene-environment interactions, a theme developed in both a clinical context regarding exercise and hypoxia, as well as in native populations living in high altitudes. Furthermore, experts in the field have combined topics such as skeletal muscle angiogenesis and hypoxia, high altitude pulmonary edema, new insights into the biology of the erythropoietin receptor, and the latest advances in cardiorespiratory control in hypoxia. This volume explores the fields of anatomy, cardiology, biological transport, and biomedical engineering among many others.


2-Oxoglutarate-Dependent Oxygenases

2-Oxoglutarate-Dependent Oxygenases

Author: Christopher J Schofield

Publisher: Royal Society of Chemistry

Published: 2015-05-06

Total Pages: 508

ISBN-13: 1849739501

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Since the discovery of the first examples of 2-oxoglutarate-dependent oxygenase-catalysed reactions in the 1960s, a remarkably broad diversity of alternate reactions and substrates has been revealed, and extensive advances have been achieved in our understanding of the structures and catalytic mechanisms. These enzymes are important agrochemical targets and are being pursued as therapeutic targets for a wide range of diseases including cancer and anemia. This book provides a central source of information that summarizes the key features of the essential group of 2-oxoglutarate-dependent dioxygenases and related enzymes. Given the numerous recent advances and biomedical interest in the field, this book aims to unite the latest research for those already working in the field as well as to provide an introduction for those newly approaching the topic, and for those interested in translating the basic science into medicinal and agricultural benefits. The book begins with four broad chapters that highlight critical aspects, including an overview of possible catalytic reactions, structures and mechanisms. The following seventeen chapters focus on carefully selected topics, each written by leading experts in the area. Readers will find explanations of rapidly evolving research, from the chemistry of isopenicillin N synthase to the oxidation mechanism of 5-methylcytosine in DNA by ten-eleven-translocase oxygenases.


Mechanisms of Oxygen Sensing in Human Trophoblast Cells [microform]

Mechanisms of Oxygen Sensing in Human Trophoblast Cells [microform]

Author: Carla Saveria De Marco

Publisher: Library and Archives Canada = Bibliothèque et Archives Canada

Published: 2004

Total Pages: 276

ISBN-13: 9780612955653

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Early placentation occurs in a relatively hypoxic environment. As placentation progresses, the events associated with trophoblast differentiation in response to increasing oxygen are known; however, the mechanisms by which trophoblast cells 'sense' the changing oxygen tension remain unclear. HIF-1alpha mediates oxygen's effects on trophoblast differentiation. VHL has been associated with negative regulation of HIF-1alpha under oxygenated conditions. The aim of this study was to elucidate mechanisms of oxygen sensing in trophoblast cells. Mitochondrial electron transport chain interference in first trimester villous explants cultured under low oxygen inhibited extravillous trophoblast cell outgrowth associated with reduced cellular proliferation. HIF-1alpha immunoreactivity was decreased. VHL displayed a similar pattern of expression as HIF-1alpha in the first trimester and in response to varying oxygen; however, spatially they showed reciprocal regulation. Together, these findings suggest a role for the mitochondrial pathway in trophoblast cell oxygen sensing, and a role for VHL in sensing, potentially via an interaction with HIF-1alpha.


The Metabolism of Tumours

The Metabolism of Tumours

Author: Otto Warburg

Publisher: EnCognitive.com

Published: 2015-09-15

Total Pages: 359

ISBN-13: 1927091152

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This is the original text of Nobel Prize Laureate Dr. Otto Warburg's classic, "The Metabolism of Tumours." In this book Dr. Warburg, MD, PhD, and distinguished scientists demonstrate, through empirical evidence that: “Cancer, above all other diseases, has countless secondary causes. But, even for cancer, there is only one prime cause. Summarized in a few words, the prime cause of cancer is the replacement of the respiration of oxygen in normal body cells by fermentation of sugar.” All the experiments, in their original text, are included in this book.


Plant Responses to Hypoxia

Plant Responses to Hypoxia

Author: Elena Loreti

Publisher: MDPI

Published: 2021-03-02

Total Pages: 288

ISBN-13: 3036501487

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Molecular oxygen deficiency leads to altered cellular metabolism and can dramatically reduce crop productivity. Nearly all crops are negatively affected by a lack of oxygen (hypoxia) due to adverse environmental conditions such as excessive rain and soil waterlogging. Extensive efforts to fully understand how plants sense oxygen deficiency and their ability to respond using different strategies are crucial to increase hypoxia tolerance. Progress in our understanding has been significant in recent years. This topic certainly deserves more attention from the academic community; therefore, we have compiled a series of articles reflecting the advancements made thus far.


Transcription Factors and Human Disease

Transcription Factors and Human Disease

Author: Gregg L. Semenza

Publisher: Oxford Monographs on Medical G

Published: 1998

Total Pages: 396

ISBN-13: 9780195112399

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Several general principles have emerged from the study of human transcription factors. First, germline mutations in genes encoding transcription factors result in malformation syndromes in which the development of multiple body structures is affected. Second, somatic mutations involving many of the same genes contribute to tumorigenesis. Third, transcriptional regulatory mechanisms demonstrate remarkable evolutionary conservation. Fourth, prenatal development and postnatal physiology are unified by the demonstration that a single transription factor can control the proliferation of progenitor cells during development and the expression within the differentiated cells of gene products that participate in specific physiologic responses. Transcription Factors and Human Disease presents the basic science of transcriptional regulation and then describes inherited human diseases attributable to mutations in DNA sequences encoding transcription factors or their cognate binding sites. The involvement of transcription factors in somatic cell genetic diseases (cancer) and epigenetic disease (teratogenesis) is briefly discussed. The effect of specific mutations on transcription factor activity and the relationship between transcriptional dysregulation, dominant or recessive inheritance patterns, and disease pathogenesis are also explored. This book thus provides a direct connection between molecular defects in transcriptional regulation and human pathophysiology.


Oxygen Sensing

Oxygen Sensing

Author: Sukhamay Lahiri

Publisher: CRC Press

Published: 2003-04-15

Total Pages: 756

ISBN-13: 082474845X

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Reviewing research on the molecular basis of oxygen homeostasis, this text describes the changes in intracellular signalling and gene expression that lead to physiological responses to hypoxia in unicellular, invertebrate, and mammalian species. It examines O2 sensing systems in bacteria and archaea and demonstrates interrelationships among cell pr